riski5 — Helsinki Functional Programming meetup presentation

Slide deck for the 2026-05-05 Helsinki Functional Programming meetup talk on building riski5 — a RISC-V soft core in Clash (Haskell), running on a 22-year-old Altera DE2 FPGA, with Linux 6.18.22 booting on real silicon.

The deck is plain HTML5 (Pandoc DZSlides), arrow-key navigable, and deployed via GitHub Pages from master/docs/.

Live deck

→ https://purefunsolutions.github.io/riski5-helsinki-functional-programming-meetup-presentation/

(Once GitHub Pages is enabled — see Deploying below.)

Keyboard navigation:

Key	Action
→ / ↓ / Space	next slide
← / ↑	previous slide
Home	first slide
End	last slide

Local preview

nix develop                 # ghc, cabal, hakyll, pandoc, graphviz, …
cabal run site -- watch     # http://localhost:8000, live-reload

To build once into docs/ (the deployed artifact):

cabal run site -- build

To wipe _cache/ + docs/:

cabal run site -- clean

Editing the deck

• Slides are a single Markdown file: SLIDES.md
• ## Heading is one slide (because --slide-level=2)
• # Heading introduces a section cluster (becomes a title slide)
• Diagrams: edit assets/diagrams/*.dot and Hakyll re-renders to SVG via the dot CLI on save (when running under cabal run site -- watch)
• Custom CSS in assets/css/overrides.css (lambda-corner branding, font tweaks)

Deploying to GitHub Pages

1. Push master to GitHub
2. Repo → Settings → Pages → Source: Deploy from a branch
3. Branch: master, folder: /docs
4. Wait ~60 s, deck is live at the URL above

The built artifact (docs/) is committed alongside source — no CI required. Rebuild locally before each push.

Format / lint

nix fmt                     # alejandra + fourmolu + prettier + deadnix + statix
nix flake check             # REUSE compliance + treefmt --ci

Licensing

Dual-licensed:

• Code (site.hs, flake.nix, nix/*, cabal.project, presentation.cabal, fourmolu.yaml) — MIT
• Content (SLIDES.md, assets/css/*, assets/diagrams/*, assets/images/*, README.md, CLAUDE.md) — CC-BY-4.0

Per-file SPDX headers are enforced via nix flake check (REUSE 6.x).

The Pure Fun Solutions lambda logo (assets/images/lambda-logo.png) is copied from https://github.com/purefunsolutions/purefun-front.

Sibling repos

• alterade2-flake — Quartus II 13.0sp1 + USB-Blaster on NixOS
• verilambda — Haskell-Verilator bindings, type-preserving
• riski5 — the RISC-V core itself